1. Field of the Invention
The present invention generally relates to a positioner and a probe head, and more particularly, to a positioner of a probe card and a probe head of a probe card.
2. Description of Related Art
Semiconductor integrated circuit chip typically adopts a probe card to perform an electrical testing. The probe card includes a printed circuit board, a space transformer and a probe head. The probe head at least includes an upper guide plate, a lower guide plate and a plurality of probes. The upper guide plate and the lower guide plate of the probe head typically have a plurality of through holes, and each through hole can only be passed by a single probe. Thus, when a under test contact pitch of the chip becomes smaller, a corresponding testing pitch of the probe head must also become smaller in correspondence, so as to be qualified as a fine pitch.
As shown in FIG. 1, a typical probe head 80 that is used in testing the semiconductor chip includes an upper guide plate 81, a lower guide plate 82 and a plurality of probes 90. As shown in FIG. 2, a cross-section of a head portion 92 of each probe 90 substantially appears to be a circle, and a cross-section of a body portion 94 of each probe 90 substantially appears to be an ellipse or a rectangle; and in order to facilitate in an assembling of each component of the probe head 80, the head portion 92 of each probe 90 is usually positioned in a positioner 84 in the first, wherein the positioner 84 has a plurality of openings 85 passing through the positioner 84. A shape of each opening 85 is formed by superimposing a circle and an ellipse. The circular portion in the each opening 85 is similar to a cross-sectional shape of the head portion 92 of each probe 90. The head portion 92 of each probe 90 is inserted into each opening 85 of the positioner 84, so that the openings 85 may constrain the probes 90 and further be disposed into upper through holes 86 of the upper guide plate 81, thereby enabling the body portion 94 of each probe 90 to extend to the lower guide plate 82.
When assembling the probe head 80, each probe 90 can pass through each opening 85 of the positioner 84 after the positioner 84 is firstly disposed at the lower guide plate 82, and the body portion 94 of each probe 90 that appears to be in an elliptical cross-sectional shape would also pass through the elliptical portion of each opening 85 so as to prevent each probe 90 from producing structural damage due to having mutual interference contacts with a wall-surface of each opening 85. However, after gone through practical application, it is discovered that the openings 85 are unable to produce an effective positioning effect to the head portions 92 of the probes 90, and thus is due to the reason that the head portions 92 of the probes 90 would move from the circular portions of the openings 85 towards the elliptical portions just by being subjected to a little force. As a result, all the probes 90 would shake or deviate from the positions due to the reason that the openings 85 being too large, thereby causing the head portions 92 of all the probes 90 unable to be uniformly aligned and pass through the upper through holes 86 of the upper guide plate 81; and therefore, the positioning effect of the probes 90 is poor, difficulty in assembling is increased, and a product yield is lowered.
On the other hand, it can be seen from FIG. 3 that, enlarged openings 85 would cause a distance D10 between the openings 85 to be shortened. In a probe head 80 that adopts the fine pitch as depicted in FIG. 1 without increasing the pitch, if it is to switch to the probe 90 with a larger probe diameter, then the distance D10 between the openings 85 would be shortened even more, thereby causing a significant increase in the probability of cracking at this certain location of the positioner 84; and as a result, the difficulty in assembling is further increased, and the product yield is further lowered. Therefore, how to effectively solve the aforementioned shortcomings is the foremost goal in need to be addressed by related practitioners.